Damien Chazelle knows what the hell he's talking about. Whiplash's twenty-nine-year-old writer/director went through the ringer as a music student, and came out the other side an accomplished, inspiring filmmaker. His story of a first-year drummer at a prestigious New York jazz conservatory (whose hard-nosed instructor pushes the limits of his drive and abilities) is lively, bloody, and merciless. We've seen art-school dramas before, but rarely do they get the details so right.

Miles Teller plays Andrew, a hot-shot jazz obsessive who, like his classmates, wants nothing more than to win the approval of top instructor Terence Fletcher (J.K. Simmons)l--and a spot in his elite band of upper classmen. Familiar as the premise may sound, this is not Fame, which followed multiple students on their journey to musical greatness. Nor is it An Officer and a Gentleman, wherein the broken-down-by-his-superior-officer soldier still finds time to get the girl by the end credits. Whiplash strays into Full Metal Jacket territory, with a hellfire confrontation between Fletcher and a chubby, insecure student (C.J. Vana), whom he nicknames "Elmer Fudd". But it's not a riff on that movie, either.

Chazelle zeroes in on Andrew's obsession with greatness. The kid practices for hours every day. He barely sleeps, and sometimes carves out time to catch a movie with his dad (Paul Reiser). He meets a student from another school, named Nicole (Melissa Benoist), and they sneak around on Andrew's muse: the sweaty, unforgiving pursuit of jazz mastery.

Andrew believes that notoriety in Fletcher's band will accelerate his education and career. His focus narrows dangerously, and he drifts into an underhandedness that leaves us wondering: can one be great if they waste time being a decent person? If so, is greatness worth pursuing? Chazelle poses this question a few different ways: at a contentious dinner between Andrew and his college-jock cousins; during a hard conversation with Nicole, during which Andrew checks out and his ambitions take over; and in a dozen close-ups of gaping finger wounds and blood spattering across cymbals like water in a sizzling pan. Whiplash is a possession movie in search of an exorcist, where the tormented soul must decide whether or not it wants to actually disentangle itself from the demon within.

Whiplash mostly knocked my socks off. Chazelle establishes a narrative rhythm that harmonizes perfectly with soul-screaming music and two lead performers who will command attention and appreciation once this film goes wide. Teller continues to explore his range as the cocky outcast; having recently graduated from high-school-student roles (with memorable turns in the Footloose remake and, especially, in last year's The Spectacular Now), his latest films feature not-quite-adult characters bobbing for air in the real world. What Andrew lacks in interpersonal skills (he's literally been locked up in padded rooms most of his life, playing drums) he makes up for in drive and ability. Teller doesn't play like an actor who had to learn a skill for a part: to this non-jazz aficionado, he was utterly convincing as a born performer wringing every bit of fluid from his body to achieve perfect time.

The same is true for Simmons. He's the drill instructor, the twisted authority figure, the cranky boss from hell. In short, he's a composite of his two most famous characters: Oz's white-supremacist bully and Spider-Man's blow-hard newspaper editor. His performance is grounded in empathy and compassion for kids who don't realize how damned hard it is to make it as a musician--especially at the level they aspire to. When Fletcher holds up a session for six hours in the middle of the night, so that three students can squeeze out a couple of notes to his exacting standards, I felt the exhaustion, the throbbing muscles, the disappointment. But I also appreciated Simmons' ability to sell us on a teacher determined to not let mediocrity pass (at one point, he admonishes Andrew, "There are no two words in the English language than 'good job'").

Despite this considerable praise, Whiplash finds itself out of tune in more parts than I'm comfortable giving a pass. Though cutting and delivered with conviction, Simmons' dialogue is often attention-grabbing in all the wrong ways. His slurs against races, sexes, and the mentally challenged feel forced--as if Chazelle didn't think we'd get just how intimidating Fletcher is without cartoonish diatribes. In fact, there's more intimidation in Simmons' reflexive, stop-the-music fist gesture than in any challenge to a mousy student's masculinity.

I also didn't appreciate the utter lack of repercussion in one character's two obvious crimes: an instance of public assault, and another of leaving the scene of an accident. In the moment, these scenes work very well, dramatically--but I was left scratching my head for minutes afterwards when the next plot progression didn't involve this person skipping practice to meet with a parole officer.

There's a final itch I just can't scratch here, one that would plant us firmly in spoiler territory. I'll leave it alone for now, except to ask anyone who's seen Whiplash whether or not they "get" Reiser's character's reaction to Andrew's big decision at the climax of the film. It's a puzzling note that feels disappointingly false.

Quibbles aside, Whiplash is one of my favorite films of the year. You'll be hard-pressed to find two more passionate, committed performances in 2014 than those of Teller and Simmons. And Chazelle announces himself as a young creative force to be reckoned with. Just as Billy Bob Thornton blew up after turning a short film into 1996's Academy Award-nominated Sling Blade, Chazelle expands his own short as a feature-length powder keg that, I hope, will ensure we hear more from him in years to come. His honest, refreshing voice made my spirit dance like a fool.